FLEXIBLE CIRCUIT BOARD AND PROCESS FOR PRODUCING THE SAME

摘要

A flexible circuit board comprises a substrate which has a polyimide layer recessed to define at least a compartment. The compartment includes an inner wall surface having a side wall and a bottom wall. The compartment is for containing a multilayer unit, wherein the multilayer unit includes an adhesion enhancing layer formed on the wall of the compartment, a first electrically conducting layer disposed on the adhesion enhancing layer, and a second electrically conducting layer formed on the first electrically conducting layer. The adhesion enhancing layer is palladium. The first electrically conducting layer is nickel. The substrate is composed of polyimide (PI).

主权项

1. A method of manufacturing a flexible circuit board, comprising:
providing a substrate having an upper surface and a lower surface; forming a polyamic acid layer on the surface of the substrate, and conducting a first pre-curing process on the polyamic acid layer such that the polyamic acid layer is semi-cured; depositing a photoresist on the polyamic acid layer, and conducting a second pre-curing process on the photoresist and the polyamic acid layer; exposing and developing the photoresist according to a circuit configuration diagram to partially remove the photoresist and the polyamic acid layer thereunder, partially revealing the surface of the substrate and leaving a remaining photoresist and a remaining polyamic acid layer thereunder, wherein the remaining polyamic acid layer and the remaining photoresist jointly defines a compartment having an inner wall surface including at least a side wall and a bottom wall; forming an adhesion enhancing layer on the side wall and the bottom wall by using an adhesion enhancer; forming a first electrically conducting layer on the adhesion enhancing layer to fix the first electrically conducting layer on the bottom wall and the side wall; removing the remaining photoresist and revealing the polyamic acid layer thereunder; curing the remaining polyamic acid layer which becomes a polyimide, forming a precursor substrate; plating a second electrically conducting layer on the surface of the precursor substrate, selectively forming an electric circuit with the first electrically conducting layer and the adhesion enhancing layer in the compartment of the precursor substrate; and forming an electrically insulating layer on the surface of the precursor substrate to cover the electric circuit and the polyimide on the surface of the precursor substrate.